Variable-speed drive



Sept. 19, 1950 R. P.- BECHLE VARIABLE SPEED DRIVE 2 Sheets-Sheet 1 Filed Jan. 10, 1947 YINVENTOR. M W M ATTORNEY Sept. 19, 1950 R. P. BECHLE 2,522,559

VARIABLE SPEED DRIVE Fil ed Jan. 10, 1947 2 Sheets-Sheet 2 Patented Sept. 19, 1950 UNITED STATES PATENT OFFICE VARIABLE-SPEED DRIVE Rudolph P. Bechle, Yonkers, N. Y., asiignor to Potdevin Machine Company, Brooklyn, N. Y., a corporation of New York Application January 10, 1947, Serial No. 721,201

6 Claims. 1

My invention relates to machines on which operations are carried out on a continuous web and in which changes in length are required.

For purposes of illustration and clarity of description, I will describe my invention as applied to a multi-size rotary web printing press, it being understood, however, that the invention is equally useful with other machines such as sheeters, bag machines, bag tubers, etc.

One of the objects of my invention is to provide mechanism which is completely self-adjusting thereby eliminating all possibility of human error.

A further object of my invention is to provide mechanism of such a nature that the speed of corrective rotation impressed on the transmission adjustment is proportional to the amountof correction required. This eliminates any possibiity of hunting or over-correction in alternate direction.

A further object of my invention is to provide a differential variable speed drive for multi-size printing presses wherein and whereby the peripheral speed of the plate, blanket and impression cylinders will always be the same as the paper speed, despite changes in sizes on the press.

In multi-size rotary printing presses for operation on a continuous web there are usually two sets of mechanisms. The first of these mechanisms comprises the plate cylinders, in some instances blanket cylinders, and also impression cylinders if a tympan sheet is used. All of these cylinders must make one revolution or an integral number of revolutions per impression.

The second set of mechanisms comprises the inking cylinders, paper feed rollers, and sometimes impression cylinders if a continuous surface cylinder is used. The size of these elements is constant, and they must all be driven at some fixed ratio to the speed of the web, such that their surface speed is equal to web or paper speed.

Where sizes on such presses are changed, it is necessary to change the plate, blanket, and impression cylinders, so that their effective circumference is equal to the print length desired or an integral mulitple thereof; at the same time, it is to be noted that the periphery of these cylinders essentially must at all times operate at web speed.

It becomes necessary, therefore, to provide some type of speed changing equipment between these two mechanisms.

In the past, it has been customary practice to operate the change-size cylinders by means of gears mounted on the end of each cylinder shaft, the printing circumference usually being equal to the pitch circumference of the gear used. Consequently, a fixed pitch is selected initially, and thereafter all sizes possible are those which match the pitch circumferences of the pitch system in use.

These gear pitch steps present an objectionable limitation. Accordingly, to minimize this limitation, presses were built with finer and finer pitches to reduce the size of the increments. The gears, however, in conventional arrangements must transmit considerable power, so that it became necessary to' construct the gears of expensive high strength alloys.

Such a system, it is apparent, is limited to certain steps and requires a change gear for each change in cylinder size. These gears for a 36" length must be roughly 12" in diameter, and a set of eight gears per size, which is the number required on a four-color press with tympan impression cylinders, in high strength alloys represents an objectionable investment, this investment being multiplied by the number of sizes in question.

In an efiort to mitigate the inherent disadvantages above referred to, presses have been built in which the impression speed drives are grouped and the paper speed drives are grouped, and the two groups are connected by an infinitely variable speed device. In such an arrangement there is no fixed increment between sizes, and no gears are required on the change size cylinders. However, the adjustment of the variable speed device is so diflicult that the operator has a great deal of difliculty to make even a sufficiently close approximation, and it is virtually impossible for the operator to adjust as closely as the gear system previously used. Improper adjustment results in plate and ink roller-wear, smeared printing and torn paper, the degree of difiiculty being a function of the amount of misadjustment.

The present invention provides mechanism which is so constructed and arranged as to provide for automatic and accurate adjustment of the variable speed device to the proper ratio for the cylinder size and use.

In the accompanying drawings:

Fig. 1 is an elevational view of an embodiment of my invention;

Fig. 2 is an elevational view of the left hand end of Fig. 1;

Fig. 3 is an elevational view of the opposite end of the machine;

Fla. 4 is a plan view of the variable speed device; and

Fig. 5 is a similar view of the differential.

Referring to the drawings in detail, 2 designates a shaft which is suitably geared to all of the cylinders in the press which operate at a constant ratio with web speed, such as the inking rollers, paper feed rollers, etc. For clarity, this shaft will be referred to as the web shaft.

4 designates a shaft which is suitably geared to all the cylinders in the press which operate at a constant ratio with impression speed, such as the plate cylinders, blanket cylinders, etc. For clarity, this shaft will be referred to as the impression shaft.

I designates a variable speed device, such as that sold commercially as P. I. V., the input shaft I of which is geared to shaft 2 through gears 8, the output shaft 8 of this device being geared to the shaft 4 through gears l0.

Suitably mounted adjacent the variable speed device 6 is a differential ll of the Reeves type, for example, and comprising input shafts l2 and I4, respectively, and output shaft 16. This differential is so arranged that, if the input shafts I2 and I4 are rotated in opposite directions at the same speed, the output shaft It will remain stationary. On the other hand, if the two input shafts l2 and I4 are rotated at different speeds, the output shaft It will be caused to rotate at a speed which is proportional to the deviation from the same speed of rotation of th input shafts.

The output shaft l8 of the differential is geared, as by chain and sprocket drive l8, to the speed adjusting shaft of the variable speed device 6. The direction of rotation of the differential output shaft l6 depends upon which of the input shafts l2 and ll of the differential is running the faster, so that the direction of rotation of the adjusting shaft 2| of the variable speed device depends upon which of the shafts l2 and I4 of the differential is running the faster.

The input shaft l2 of the differential is geared, as by chain and sprocket drive l3, to the shaft 2.

The input shaft l4 of the differential carries a gear 22. meshing with intermediate 24, which in turn meshes with change gear 26, carried on a shaft 28. This shaft also carries a gear 30, meshing with gear 32 on the shaft 4. The gears 22, 24, 26 and 28 constitute a pilot change gear arrangement. By changing these gears to the desired ratio, the mechanism is set up for the desired ratio. It will be understood that the desired ratio is that ratio which maintains equal peripheral speed of the impression and plate cylinders with those of the feed rollers and inking rollers. This ratio changes when the print length of the press is changed, due to the fact that differences in print length require different plate and impression cylinder diameters.

As above pointed out, the shaft 2 is geared to all of the shafts in the press which operate at a constant ratio with paper speed, while the shaft 4 is similarly geared to all shafts in the press which operate at a constant ratio with impression speed. Consequently, with the arrangement of change gears shown in full lines, it is to be assumed that the shafts 2 and 4 are running at the desired relative speeds, at which time the input shafts l2 and ll of the differential II are running at the same speeds, so that shaft 16 of the differential and, hence, the adjusting shaft 20 of the variable speed device 6 are standing still, so that there is no adjustment of th variable speed device.

However, if the shafts 2 and 4 are not running at the desired relative speeds, then input shafts l2 and I4 of the differential will no longer run at equal speeds, and the output shaft 16 will be rotated in the proper direction to rotate the adjusting shaft 20 of the variable speed device to make the necessary alteration in the relative speeds of 2 and 4, the shaft 4 being driven from 2 through the variable speed device, until the shafts 2 and 4 are again running at the proper ratio, whereupon rotation of the output shaft l6 of the differential and, hence, of the adjusting shaft 20 of the variable speed device will stop.

Now, if press size is changed, which means that the relative speeds of shafts 2 and 4 are changed, it is merely necessary to substitute change gear 34 for change gear 26 and shift gear 24 to the broken line position shown in Fig-3, whereupon the differential II will function to correct the speed of shaft 4 to conform to the new ratio desired, whereby the speed of shaft 4 will be such that th cylinders geared thereto will make one revolution per impression and their peripheries will operate at paper speed.

It must be understood that changes in construction and arrangement of parts may be made within the purview of my invention.

What I claim is:

1. A differential variable speed drive for machines on which operations are carried out at spaced areas on a continuous web and in which changes in the spacing of these areas are required, said drive comprising in combination afirst shaft operating at a constant ratio with respect to web speed, a second shaft, a variable speed device for driving the second shaft from the first shaft, and a differential having an input shaft driven by the first shaft, another input shaft for the differential, a chan e gear drive between the last mentioned input shaft and the said second shaft, an adjusting shaft for the variable speed device and an output shaft for the differential for rotating the adjusting shaft of the variable speed device to maintain a predetermined ratio between the speeds of the first and second shafts.

2. A differential variable speed drive for rotary printing presses, said drive comprising in combination a web shaft operating at a constant ratio with respect to web speed, an impression shaft to be operated at a constant ratio with respect to impression speed, a variable speed device through which the said impression shaft is driven from the web shaft; a differential having an input shaft driven by the web shaft, another input shaft for the differential, a change gear driven between the impression shaft and the second mentioned differential input shaft, and an output shaft for said differential for varying the setting of the variable speed device to maintain a predetermined ratio between the speeds of the web shaft and impression shaft.

3. A differential variable speed drive for rotary printing presses said drive comprising in combination a web shaft operating at a constant ratio with respect to web speed, an impression shaft to be operated at a constant ratio with respect to impression speed, a variable speed device through which said impression shaft is driven by the web shaft, a differential having two input shafts and an output shaft and so constructed that the output shaft remains stationary when the input shafts are rotating at equal speeds but is rotated when the input shafts are rotated at unequal speeds, one of the differential input shafts being geared to the said web shaft, the

assasso other differential input shaft being geared to said impression shaft, the said output shaft of the differential being geared to the said variable speed device to adjust the same, whenever the relative speeds of the web and impression shafts vary so that the input shafts of the differential are rotated at unequal speeds thereby automatically to restore the impression shaft to its original speed.

4. A differential variable speed drive for rotary printing presses, said drive comprising in combination a web shaft operating at a constant ratio with respect to web speed, an impression shaft to be operated at a constant ratio with respect to impression speed, a variable speed device equipped with an input shaft geared to the s aid web shaft and with an output shaft geared to said impression shaft to provide a drive between the web and impression shafts, an adiusting shaft for the variable speed device to alter the speed relation between the said input and output shafts, a differential comprising two input shafts, one of which is geared to the web shaft and the other of which is geared to the impression shaft, an output shaft for the differential, gearing between the differential output shaft and to the differential input shafts so that the output shaft will be rotated when the input shafts rotate at different speeds and will remain stationary when these two shafts are rotating at the same speed, gearing between said differential output shaft and the adjusting shaft of the variable speed device so that upon rotation of said differential output shaft due to variation in the relative speeds of the web shaft and impression shaft, the setting of the variable speed device will be altered, to reestablish the relative speeds of the web shaft and impression shaft.

5. A drive for multi-size rotary printing presses comprising in combination with the web shaft and impression shaft of the pres a variable speed device constituting a driving connection between the two shafts, adjusting mechanism for the varishaft geared to the web shaft,

able speed device and comprising a differential, two input shafts for the differential, gear trains size of an impression cylinder the change gearing can be changed so that the variable speed device will automatically be reset to establish and main tain the proper relation between the speeds of the web and impression shafts. I I

. 6. A drive for multi-size rotary printing presses comprising in combination with the web shaft and impression shaft of the press a variable speed device having an input shaft geared to the web shaft and an output shaft geared to the impresssion shaft, an adjusting shaft for varying the setting of the variable speed device, a differential having an input shaft geared through change gearing to said impression shaft, and an input an output shaft for the differential geared to the adjusting shaft of the variable speed device, whereby the change gearing can be changed upon a change in impression cylinder diameters corresponding to the speed of the impression shaft.

RUDOLPH P. BECHLE.

REFERENCES CITED The following references are of record in the die of this patent:

UNITED STATES PATENTS Number Name Date 1,685,186 La France Sept. 25, 1928 1,906,831 Baker et a1 May 2, 1933 2,334,074 Coy Nov. 9, 1943 2,384,776 Troflmov Sept. 11, 1945 2,417,780 Parvin Mar. 18, 1947 FOREIGN PATENTS Number Country Date 483,343 Great Britain Apr. 19. 1938 

